The overall objectives of this three year project, which is now nearing the end of its first year, is to increase our understanding of the information content of the medical record, particularly with respect to the temporal dimension of information and information about processes. The constituents of a model of the medical record have now been designed. They include provision for representing categorical information: information about what has actually taken place; hypothetical information: information about what is possible or expected; and verificational information: information about the determination of information. The proposed work for the following year is the design and implementation of a modest information storage and retrievel system based on this model. The system will have provisions for reviewing individual records at different times, and at different levels of detail. It will also allow the selection of cases with common historical patterns from a data base of medical case histories. During the third year of this project, the system will be put to use in a medical environment to assess its usefulness.